I suspect the problem is probably a mix up with the quest script triggers in that the script thinks you made it to Reddock without Gorn. All I can say is try it again keeping behind - and in sight of - Gorn at all times until he stops just outside the base entrance. He should be standing waiting for you so he can deliver his "well here we are" message.

All the Gothic 3 “follow the NPC” quests are very easy to break because the NPCs frequently fall/walk through the world mesh. Patch 1.12 has done little to improve this.